Apparatus and method for performing uplink power control in wireless communication system supporting carrier aggregation

ABSTRACT

A method of an apparatus controls transmit power of uplink channels in a wireless communication system. The method includes configuring, for a UE, a primary serving cell on which a first uplink control channel is transmitted from the UE, configuring, for the UE, a secondary serving cell on which a second uplink control channel is transmitted from the UE, configuring a first TPC command and a second TPC command in a single TPC command group, the first TPC command being associated with transmit power of the uplink control information of the primary serving cell, the second TPC command being associated with transmit power of the uplink control information of the secondary serving cell, scrambling downlink control information based on an identifier associated with a TPC, the downlink control information comprising the single TPC command group; transmitting, to the UE, a downlink control channel comprising the scrambled downlink control information.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/343,524, filed on Nov. 4, 2016, which is a continuation of U.S.patent application Ser. No. 15/008,240, filed on Jan. 27, 2016, now U.S.Pat. No. 9,503,990, which claims priority from and the benefit of KoreanPatent Application Nos. KR10-2015-0015503, filed on Jan. 30, 2015, andKR10-2015-0015415, filed on Jan. 30, 2015. All of the afore-mentionedpatent applications are hereby incorporated by reference in theirentireties.

BACKGROUND FIELD

The present disclosure relates to wireless communication, and moreparticularly, to an apparatus and a method for performing uplink powercontrol in a wireless communication system supporting carrieraggregation.

DISCUSSION OF THE BACKGROUND

Carrier aggregation (CA) is used to support a plurality of carriers andis also referred to as spectrum aggregation or bandwidth aggregation.Each aggregated carrier by CA is referred to as a component carrier(CC). Each CC is defined by a bandwidth and center frequency. In CA, aplurality of physically continuous or non-continuous bands is aggregatedin the frequency domain, thereby exhibiting an effect of using alogically wider band.

CA basically needs a primary serving cell (PCell) serving as an anchorin communications and a secondary serving cell (SCell). In existingLong-Term Evolution (LTE), an uplink control channel, such as a physicaluplink control channel (PUCCH), is transmitted only in the PCell.

Meanwhile, uplink transmission power control of a user equipment (UE) isa technique for solving interference or attenuation according to adistance between the UE and a base station (BS), which is also referredto as a transmission power control (TPC) command. The TPC command issignaling transmitted to the UE from the BS in order to perform powercontrol of a PUCCH or physical uplink shared channel (PUSCH). The TPCcommand allows the BS to receive an uplink signal with a constantintensity of power.

Currently, a TPC command for a PUCCH or PUSCH is applied to a CAsupporting UE and a CA non-supporting UE through a common control regionof a PCell. The present disclosure suggests a new power control methodfor a PUCCH or PUSCH transmission of various serving cell groupconfigurations.

SUMMARY

An exemplary embodiment provides an apparatus and a method forperforming uplink power control in a wireless communication systemsupporting carrier aggregation.

According to one or more exemplar embodiment, a base station, e.g., anevolved NodeB, controls transmit power of uplink channels in a wirelesscommunication system. The base station may include a system including aprocessor, an RF module, and a memory. For example, the system of thebase station may include the processor 1060, the RF module 1065, and thememory 1055 shown in FIG. 10.

In an example, one or more processors of the base station may configure,for a UE, a primary serving cell on which a first uplink control channelis transmitted from the UE. The first uplink control channel may includeuplink control information of the primary serving cell. The one or moreprocessors of the base station may configure, for the UE, a secondaryserving cell on which a second uplink control channel is transmittedfrom the UE. The second uplink control channel may include uplinkcontrol information of the secondary serving cell. Further, the one ormore processors of the base station may configure a first TPC commandand a second TPC command in a single TPC command group, the first TPCcommand being associated with transmit power of the uplink controlinformation of the primary serving cell, the second TPC command beingassociated with transmit power of the uplink control information of thesecondary serving cell.

The one or more processors of the base station may scramble downlinkcontrol information based on an identifier associated with a TPC. Thedownlink control information includes the single TPC command group.

One or more RF modules may transmit, to the UE, a downlink controlchannel including the scrambled downlink control information.

According to one or more exemplary embodiment, a system of a basestation to transmit a TPC command in a wireless communication systemsupporting CA is provided.

One or more RF modules of the base station may establish a connectionwith a UE through a primary serving cell (PCell), and transmit, to theUE, a Radio Resource Control (RRC) message. The RRC message may includea first Transmit Power Control (TPC) index associated with a PhysicalUplink Control Channel (PUCCH) transmission on the PCell and a secondTPC index associated with a PUCCH transmission on a secondary servingcell (SCell), the SCell together with the PCell being configured asserving cells for the UE.

The one or more RF modules may transmit a Physical Downlink ControlChannel (PDCCH) by mapping the PDCCH to a common search space of thePCell. A Downlink Control Information (DCI) format of the PDCCH mayinclude a first TPC command for controlling transmit power of the PUCCHtransmission on the PCell and a second TPC command for controllingtransmit power of the PUCCH transmission on the SCell.

One or more processors of the base station may determine a value of thefirst TPC command to control transmit power of the PUCCH transmission onthe PCell and determine a value of the second TPC command to controltransmit power of the PUCCH transmission on the SCell, the value of thefirst TPC command being mapped in the DCI format based on the first TPCindex and the value of the second TPC command being mapped in the DCIformat based on the second TPC index.

According to one or more exemplary embodiment, a system for a UE toreceive a TPC command in a wireless communication system supporting CAis provided. The system for the UE may include a processor, an RFmodule, and a memory. For example, the system may be a system-on-chipand may include the processor 1010, the RF module 1020, and the memory1025 shown in FIG. 10.

An RF module of the system may be configured to establish a connectionwith a base station through a primary serving cell (PCell), and toreceive a Radio Resource Control (RRC) message. The RRC message mayinclude a first Transmit Power Control (TPC) index associated with aPhysical Uplink Control Channel (PUCCH) transmission on the PCell and asecond TPC index associated with a PUCCH transmission on a secondaryserving cell (SCell), the SCell together with the PCell being configuredas serving cells for the UE.

A processor of the system may be configured to detect a PhysicalDownlink Control Channel (PDCCH) by monitoring a common search space ofthe PCell. A Downlink Control Information (DCI) format of the PDCCH mayinclude a first TPC command for controlling transmit power of the PUCCHtransmission on the PCell and a second TPC command for controllingtransmit power of the PUCCH transmission on the SCell. The processor maybe configured to identify the first TPC command and the second TPCcommand from the DCI format based on the first TPC index and the secondTPC index, respectively, to control transmit power of the PUCCHtransmission on the PCell based on a value of the first TPC command, andto control transmit power of the PUCCH transmission on the SCell basedon a value of the second TPC command.

According to one or more exemplary embodiments, power control for aPUCCH or PUSCH configured on a secondary serving cell may be performed,thereby effectively supporting CA in LTE.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a wireless communication systemaccording to one or more exemplary embodiments.

FIG. 2 illustrates an example of application of a TPC command in achannel structure of a serving cell according to one or more exemplaryembodiments.

FIG. 3 is a flowchart illustrating uplink power control according to oneor more exemplary embodiments.

FIG. 4 illustrates an example of a corresponding relationship between aTPC index and a group TPC command.

FIG. 5 illustrates a method of transmitting a group TPC command andperforming monitoring according to one or more exemplary embodiments.

FIG. 6 illustrates a method of transmitting a group TPC command andperforming monitoring according to one or more exemplary embodiments.

FIG. 7 illustrates a method of transmitting a group TPC command andperforming monitoring according to one or more exemplary embodiments.

FIG. 8 illustrates a method of transmitting a group TPC command andperforming monitoring according to one or more exemplary embodiments.

FIG. 9 illustrates an example of a corresponding relationship between aTPC index and a group TPC command according to one or more exemplaryembodiments.

FIG. 10 is a block diagram illustrating a user equipment and a basestation according to one or more exemplary embodiments.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Exemplary embodiments will be described more fully hereinafter withreference to the accompanying drawings, in which exemplary embodimentsof inventive concept are shown. Throughout the drawings and the detaileddescription, unless otherwise described, the same drawing referencenumerals are understood to refer to the same elements, features, andstructures. In describing the exemplary embodiments, detaileddescription on known configurations or functions may be omitted forclarity and conciseness.

Further, the terms, such as first, second, A, B, (a), (b), and the likemay be used herein to describe elements in the description herein. Theterms are used to distinguish one element from another element. Thus,the terms do not limit the element, an arrangement order, a sequence orthe like. It will be understood that when an element is referred to asbeing “on”, “connected to” or “coupled to” another element, it can bedirectly on, connected or coupled to the other element or interveningelements may be present.

FIG. 1 illustrates a wireless communication system according to one ormore exemplary embodiment.

Referring to FIG. 1, the wireless communication system 10 is widelylocated to provide a variety of communication services such as a voiceservice and a packet data service. The wireless communication system 10includes one or more evolved-NodeBs (eNBs) 11. Each eNB 11 provides acommunication service to a predetermined cell, for example, cells 15 a,15 b, and 15 c. Here, the cell may be divided into a plurality of areas(also, referred to as sectors).

User equipment 12 (UE) may be located at a certain location or portable,and may also be referred to as different terms, including MS (mobilestation), MT (mobile terminal), UT (user terminal), SS (subscriberstation), wireless device, PDA (personal digital assistant), wirelessmodem, and handheld device. An eNB 11 may also be referred to as BS(Base Station), BTS (Base Transceiver System), Access Point, femto basestation, Home nodeB, relay and the like. A cell inclusively refers tovarious coverage areas, such as mega cell, macro cell, micro cell, picocell, and femto cell. A cell may be used as a term for indicating afrequency band that a BS provides, a coverage of a BS, or a BS.

Hereinafter, the term downlink refers to communication from a basestation 11 to a UE 12, and the term uplink refers to communication froma UE 12 to a base station 11. For downlink, a transmitter may be part ofa base station 11, and a receiver may be part of a UE 12. For uplink, atransmitter may be part of a UE 12 and a receiver may be part of a basestation 11. There is no limitation in the multiple access method appliedto a wireless communication system. Diverse methods can be used,including CDMA (Code Division Multiple Access), TDMA (Time DivisionMultiple Access), FDMA (Frequency Division Multiple Access), OFDMA(Orthogonal Frequency Division Multiple Access), SC-FDMA (SingleCarrier-FDMA), OFDM-FDMA, OFDM-TDMA, OFDM-CDMA. Uplink transmission anddownlink transmission can use either TDD (Time Division Duplex), whichuses different time locations for transmissions, or FDD (FrequencyDivision Duplex), which uses different frequencies for transmissions.

The layers of a radio interface protocol between a UE and a BS may beclassified as a first layer (L1), a second layer (L2), and a third layer(L3), based on three low layers of an Open System interconnection (OSI)model, which is well known in association with a communication system. Aphysical layer belonging to the L1 among the layers, provides ainformation transfer service using a physical channel.A physical layeris connected to a media access control (MAC) layer corresponding to anupper layer through a transport channel. Data is transferred between theMAC layer and the physical layer through the transport channel. Thetransport channel is classified based on a method used to transport datathrough a radio interface. Further, data is transferred betweendifferent physical layers, for example, between a physical layer of auser equipment (UE) and a physical layer of an eNB through a physicalchannel. The physical channel may be modulated using an orthogonalfrequency division multiplexing (OFDM) method and uses, as radioresources, a time, a frequency, and a space generated with a pluralityof antennas.

Hereinafter, a multiple carrier system includes the system that supportscarrier aggregation. Contiguous CA and/or non-contiguous CA may be usedin the multiple carrier system; in addition, both symmetric aggregationand asymmetric aggregation may be used in the multiple carrier system aswell. A serving cell may be defined as a component frequency band basedon multiple CC system which may be aggregated by CA. A serving cell mayinclude a primary serving cell (PCell) and a secondary serving cell(SCell). A PCell means a serving cell which provides security input andNon-Access Stratum (NAS) mobility information on Radio Resource Control(RRC) establishment or re-establishment state. Depends on the capabilityof a user equipment, at least one cell may be used together with a PCellto form an aggregation of serving cells, the cell used with a PCell isreferred to as an SCell. An aggregation of serving cells whichconfigured for a user equipment may include one PCell, or one PCelltogether with at least one SCell. A serving cell is activated ordeactivated.Uplink transmission power control of a UE is performed by aTransmission Power Control (TPC) command. A TPC command is a signalingthat a BS transmits to a UE in order to perform PUCCH or PUSCH powercontrol. With the introduction of a PUCCH(SCell) in LTE, when aPUCCH(SCell) is additionally configured for a CA-configured UE, aportion of pieces of uplink control information (UCI) transmitted onlyon an existing PUCCH(PCell) may be sent via the PUCCH(SCell). Also,pieces of UCI may also be sent on the PUSCH(SCell) depending on thepresence of an uplink grant. Thus, to effectively supportPUCCH(SCell)-based CA, power control for a PUCCH(SCell) or PUSCH isrequired as well as in a PCell.

FIG. 2 illustrates an example of application of a TPC command in achannel structure of a serving cell according to one or more exemplaryembodiments.

Referring to FIG. 2, a PCell and a SCell are configured by CA for a UE.PUCCH regions and PUSCH regions are divided on the frequency axis of theserving cells. Transmission power for a signal in the PUCCH regions anda signal in the PUSCH regions may be controlled by a group TPC command.The group TPC command is a TPC command for a UE group. That is, thegroup TPC command includes TPC commands respectively for a plurality ofUEs. For improving CA in LTE, a technique of transmitting a PUCCH in anSCell may be used. When a PUCCH transmission is configured in the SCellas well as in the PCell, overhead due to uplink control information(UCI) concentrated on the PCell may be reduced. Further, it is usefulfor deploying a small cell providing efficient uplink transmission. As aresult, it is possible to transmit an uplink control signal withreliability. When at least one of the UEs supports a PUCCH(SCell), thegroup TPC command may include TPC commands of the PCell and the SCellfor the same UE.

According to one or more exemplary embodiments, a base station and auser equipment may be configured to provide a radio communication schemethat supports CA of one or more SCells operating in an unlicensed bandor an unlicensed spectrum with a PCell based on a support of the PCelloperating in a licensed band or a licensed spectrum. Each band mayinclude one or more subcarriers and may be referred to as a componentcarrier.

In an example, a first UE UE1 may perform CA of carriers from among atleast five licensed carriers and an unlicensed carrier, and a second UEUE2 and a third UE UE3 may perform CA of carriers from among fivelicensed carriers and an unlicensed carrier. The first UE UE1 may beconfigured to utilize maximum 32 component carriers (CCs) and support CAof maximum 16 CCs from among the maximum 32 CCs. The first UE UE1, thesecond UE UE2, and the third UE UE3 may configure a licensed carrier asa PCell or an SCell and perform CA of the licensed carrier and anunlicensed carrier configured as an SCell. In such a scheme, variousconfigurations may be applied with respect to downlink(DL)/uplink(UL)control signaling. In order to support CA using maximum 32 CCs onphysical (PHY) layer and medium access control (MAC) layer, excessivesignaling overhead may occur. Such signaling overhead may be reducedthrough a Radio Resource Control (RRC) signaling scheme described below.

Table 1 is an example showing a scheme in which 25 CCs are divided into4 groups and configured.

TABLE 1 RRC signaling First serving cell group Second serving cell groupThird serving cell group Fourth serving cell group (SGC#0 (support(SGC#1 (support (SGC#2 (support (SGC#3 (support maximum 8 CCs)) maximum8 CCs)) maximum 8 CCs)) maximum 8 CCs)) PCell(self-scheduling)SCell#0(Cross-carrier SCell#0(Cross-carrier SCell#0(self-scheduling)scheduling) scheduling) SCell#1 SCell#1 SCell#1 SCell#1 SCell#2 SCell#2SCell#2 SCell#2 SCell#3 SCell#3 SCell#3 SCell#3 SCell#4 SCell#4 SCell#4SCell#4 SCell#5 SCell#5 SCell#5 SCell#5 SCell#6

Referring to Table 1, the number of serving cell groups may bedetermined based on the number of CCs configured in a UE and the maximumnumber of CCs configurable in one serving cell group. Table 1 shows anexample configuration when maximum 8 CCs can be configured in oneserving cell group.

In another example, two serving cell groups may be configured. In afirst serving cell group SCG#0, maximum 16 serving cells (or CCs)including a PCell may be configured. In a second serving cell groupSCG#1, maximum 16 serving cells may be configured. If a UE supportsPUCCH SCell and a base station configures the PUCCH SCell in the secondserving cell group SCG#1, maximum 16 serving cells (or CCs) includingthe PUCCH SCell may be configured in the second serving cell groupSCG#1.

The PUCCH SCell is one of SCells configured for the UE by the basestation and is a unique SCell on which a PUCCH transmission other than adefault PUCCH transmission on PCell is enabled. Through the PUCCH SCell,overhead of Uplink Control Information (UCI) transmitted by an uplink onthe PCell may be distributed (or offloaded) from the PCell to the PUCCHSCell, thereby enhancing system performance. According to one or moreexemplary embodiments, if a primary serving cell group including a PCelland a secondary serving cell group including a PUCCH SCell areconfigured for a single UE, at least two Transmit Power Control (TPC)commands for the single UE may be generated and transmitted. The singleUE may be configured with more than one PUCCH SCells and the number ofTPC commands for the single UE may increase in accordance with theincreased number of PUCCH SCells. The secondary serving cell group doesnot include a PCell.

A group of TPC commands (“TPC commands group”) may include a pluralityof TPC commands. The TPC commands group may control transmit power of anuplink transmission on serving cells in the primary serving cell group(“PUCCH PCell group”) and control transmit power of an uplinktransmission on serving cells in the secondary serving cell group(“PUCCH SCell group”). The TPC commands group may control transmit powerof a PUSCH transmission (“uplink data channel transmission”) on servingcells of the primary serving cell group and the secondary serving cellgroup as well as transmit powers of a PUCCH transmission on the PCelland a PUCCH transmission on the PUCCH SCell(s). The PUCCH of the PCellmay include UCI of the PCell and other SCells included in the primaryserving cell group, and the PUCCH of the PUCCH SCell may include UCI ofSCells included in the secondary serving cell group.

Signals in the PUCCH regions for which power is controlled by the groupTPC command may include periodic CSI reporting, HARQ-ACK, SR, or thelike.

In operations to which the group TPC command for PUCCH/PUSCHtransmission power control of each serving cell is applied, thePUCCH(PCell) is controlled by TPC command 1, and the PUCCH(SCell) iscontrolled by TPC command 2 (for convenience, a TPC command for a PUSCHis omitted in the preset embodiment).

Here, TPC commands 1 and 2 may be included in one group TPC command orin different group TPC commands. That is, TPC command 1 and TPC command2 may be provided via a piece of downlink control information (DCI) ordifferent pieces of DCI. DCI is transmitted to a UE in a common searchspace through a PDCCH.

In the present embodiment, it is assumed that one PCell and one SCellare configured for one UE and there are two TPC commands accordingly,which is provided for illustrative purpose only. Alternatively, one ormore PUCCH-configured SCells may be present for one UE, and the numberof TPC commands may increase accordingly. Although a group TPC commandis described simply as controlling a PUCCH (PCell) (hereinafter,referred to as a PUCCH(PCell)) and a PUCCH(SCell) (hereinafter, referredto as a PUCCH(SCell)) hereinafter, the group TPC command may control notonly a primary serving cell and a PUCCH(SCell) but also a PUSCH.

Hereinafter, a method of performing uplink power control by a group TPCcommand according to one or more exemplary embodiment will be describedin detail.

FIG. 3 is a flowchart illustrating uplink power control according to oneor more exemplary embodiment.

Referring to FIG. 3, a BS transmits an upper-layer message to assign aTPC index to a UE (S300). The TPC index determines an index to a TPCcommand for the UE. The TPC index may have a value of N or M, in which Nand M are distinguished based on a DCI format. For example, in the caseof DCI format 3, the TPC index has a value of N, and in the case of DCIformat 3A, the TPC index has a value of M. The upper-layer message maybe an RRC message. For example, the RRC message is TPC-PDCCH-Config,which is used to specify indexes and RNTIs for PUCCH and PUSCH powercontrol. PUCCH and PUSCH power control may be set up or canceled usingTPC-PDCCH-Config.

In the present embodiment, a plurality of TPC indexes may be present forthe UE, be assigned to a PCell and a SCell of the UE, and correspond toTPC commands for the PCell and the SCell, respectively. For example, theTPC indexes may include a first TPC index for a PUCCH(PCell) and asecond TPC index for a PUCCH(SCell). The second TPC index may be anadditional index to the first TPC index. The upper-layer message (forexample, RRC message or TPC-PDCCH-Config) for configuring both the firstTPC index and the second TPC index may have a structure in the followingtable.

TABLE 2 -- ASN1START TPC-PDCCH-Config ::=   CHOICE {   release NULL,  setup SEQUENCE {     tpc-RNTI   BIT STRING (SIZE (16)),     tpc-Index  [TPC-Index, TPC-Index_r13]   } } TPC-Index ::= CHOICE {  indexOfFormat3     INTEGER (1..15),   indexOfFormat3A     INTEGER(1..31) TPC-Index_r13(SCell PUCCH) ::=   CHOICE {   indexOfFormat3    INTEGER (1..15),   indexOfFormat3A     INTEGER (1..31) } -- ASN1STOP

Referring to Table 2, a tpc-Index field indicates [TPC-Index,TPC-Index_r13]. Here, a TPC-Index field indicates the first TPC indexand has a value of indexOfFormat3 or indexOfFormat3A according to DCIformat. indexOfFormat3 is a natural number of 1 to 15, andindexOfFormat3A is a natural number of 1 to 31. Meanwhile, a TPC-Indexr13 field indicates the second TPC index and has a value ofindexOfFormat3 or indexOfFormat3A according to DCI format.indexOfFormat3 is a natural number of 1 to 15, and indexOfFormat3A is anatural number of 1 to 31.

The UE receiving the upper-layer message uses the TPC-Index field as aTPC index to a TPC command for the PUCCH(PCell) and the TPC-Index_r13field as a TPC index to a TPC command for the PUCCH(SCell). That is, theUE may distinguish the TPC index for the PCell and the TPC index for theSCell. The first TPC index and the second TPC index may be set by the BSindependently and individually, or in connection with each other oridentically. The UE may perform power control for PUCCH(PCell) andPUCCH(SCell) transmissions using the two TPC indexes. The TPC-Index_r13field may be replaced with a name including a SCell-related term, suchas TPC-Index_SCell. Here, the PUCCH for the PCell and the PUCCH for theSCell may belong to one UE.

When the BS provides the plurality of TPC indexes set in S300 to the UE,the UE establishes TPC settings for the PCell and the SCell.

Subsequently, the BS transmits a group TPC command to the UE (S305). Thegroup TPC command is transmitted, being included in DCI. The length andcontent of the group TPC command may vary depending on a DCI format usedfor transmission of the group TPC command. In the case of DCI format 3,the group TPC command is “TPC command number 1, TPC command number 2, .. . , TPC command number N.” In the case of DCI format 3A, the group TPCcommand is “TPC command number 1, TPC command number 2, . . . , TPCcommand number M.” N and M are parameters illustrated in Table 2.According to one or more exemplary embodiment, both DCI formats 3 and 3Amay be used to transmit the group TPC command, and other DCI formats arealso available.

In order that the UE or BS performs both power control for PUCCH(PCell)and power control for PUCCH(SCell), various embodiments of group TPCcommands may be used in S305.

In one embodiment, the group TPC command is a single group TPC command,in which a single group TPC command is included in a piece of DCI. TheDCI including the single group TPC command is mapped to a PDCCHscrambled with a TPC-PUCCH RNTI and transmitted. Further, the DCIincluding the single group TPC command is transmitted on the PCell (seeFIG. 5).

For example, a corresponding relationship between a TPC index and agroup TPC command is illustrated in FIG. 4. Referring to FIG. 4, DCIformat 3 and DCI format 3A have specific lengths, which are, forexample, 11 bits in FIG. 4.

In an example of DCI format 3, UE1, UE2, and UE3 performs PUCCH powercontrol by a single group TPC command. Since a PUCCH(SCell) isconfigured only for UE1 among UE1 to UE3, an additional TPC command (2bits) for PUCCH(SCell) power control is allocated to UE1. A PUCCH(SCell)is not configured for UE2 and UE3. In DCI format 3, every two bits areone TPC command, and TPC commands sequentially correspond to particularTPC indexes, respectively. First and second bits (or TPC command 1)correspond to TPC index 1, third and fourth bits (or TPC command 2) toTPC index 2, fifth and sixth bits (or TPC command 3) to TPC index 3, andseventh and eighth bits (or TPC command 4) to TPC index 4. It is set inadvance which UE or serving cell each TPC index is for through thesignaling in Table 5. For example, TPC index 1 is for a PUCCH(PCell) ofUE1, and TPC index 4 is for a PUCCH(SCell) of UE1. That is, since thePUCCH(SCell) is configured only for UE1, the additional TPC command (2bits) for PUCCH(SCell) power control is allocated to UE1.

Next, in an example of DCI format 3A, UE1 to UE6 performs PUCCH/PUSCHpower control by a single group TPC command. Since PUCCH(SCell)s areconfigured for UE1 and UE6 among UE1 to UE6, an additional TPC command(1 bit) for PUCCH(SCell) power control is allocated to UE1 and UE6. InDCI format 3A, each one bit is one TPC command, and TPC commandssequentially correspond to particular TPC indexes, respectively. A firstbit (or TPC command 1), second bit (or TPC command 2), third bit (or TPCcommand 3), fourth bit (or TPC command 4),..., and M-th bit (or TPCcommand M) correspond to TPC index 1, TPC index 2, TPC index 3, TPCindex 4, . . . , and TPC index M, respectively. It is set in advancewhich UE or serving cell each TPC index is for through the signaling inTable 5. For example, TPC index 1 is for a PUCCH(PCell) of UE1, and TPCindex 3 is for a PUCCH(SCell)of UE1. Also, TPC index 7 is for aPUCCH(PCell) of UE6, and TPC index 8 is for a PUCCH(SCell) of UE6.

Referring back to FIG. 3, in another embodiment, the group TPC commandis multiple group TPC commands, in which a first group TPC command(PUCCH(PCell) power control) and a second group TPC command(PUCCH(SCell) power control) are included in different pieces of DCI.Both first DCI including the first group TPC command and second DCIincluding the second group TPC command are transmitted on the PCell (seeFIGS. 6 and 7).

In still another embodiment, the group TPC command is multiple group TPCcommands, in which a first group TPC command (PUCCH(PCell) powercontrol) and a second group TPC command (PUCCH(SCell) power control) areincluded in different pieces of DCI. First DCI including the first groupTPC command is transmitted on the PCell, and second DCI including thesecond group TPC command is transmitted on the SCell (see FIG. 8).

The UE receives the DCI including the group TPC command and performsPUCCH and PUSCH power control in the PCell and the SCell based on thegroup TPC command (S310). Specifically, power control according to thegroup TPC command may be performed based on an accumulative powercontrol mode. For example, when the UE receives a group TPC command fora PUCCH-configured SCell, the UE accumulates a PUCCH power control valueaccording to the group TPC command and a previous value.

For example, the UE may perform the foregoing accumulation operationbased on the following equation.

$\begin{matrix}{{g(i)} = {{g\left( {i - 1} \right)} + {\sum\limits_{m = 0}^{M - 1}{\delta_{PUCCH}\left( {i - k_{m}} \right)}}}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

δ_(PUCCH) is a value corresponding to a group TPC command indicated tothe UE through DCI format 3/3A, which is expressed in dB and illustratedin Table 3 and Table 4 below.

TABLE 3 TPC command field in DCI format 3A δ_(PUCCH) _([dB}) 0 −1 1 1

TABLE 4 TPC command field in DCI format 1A/1B/1D/1/2A/2B/2C/2D/2/3δ_(PUCCH) _([dB}) 0 −1 1 0 2 1 3 3

Referring to Table 3 and Table 4, Table 3 illustrates a mappingrelationship between a group TPC command and δ_(PUCCH) in DCI format1A/1B/1D/1/2A/2B/2C/2D/2/3, and Table 4 illustrates a mappingrelationship between a group TPC command and in DCI format 3A.

In Equation 1, g(i) represents a current PUCCH power control adjustmentstate. In FDD, M=1. In TDD, M is the number of downlink subframesassociated with transmission of one PUCCH, which may vary according todownlink HARQ timing. k_(m) is a downlink HARQ timing value indicatingeach associated downlink subframe, which refers to an n-km downlinksubframe when a current subframe is n. km is illustrated, for example,in Table 5.

TABLE 5 UL/DL subframe n configuration 0 1 2 3 4 5 6 7 8 9 0 — — 6 — 4 —— 6 — 4 1 — — 7, 6 4 — — — 7, 6 4 — 2 — — 8, 7, 4, 6 — — — — 8, 7, — —4, 6 3 — — 7, 6, 11 6, 5 5, 4 — — — — — 4 — — 12, 8, 7, 11 6, 5, — — — —— — 4, 7 5 — — 13, 12, 9, 8, 7, 5, 4, — — — — — — — 11, 6 6 — — 7 7 5 —— 7 7 —

The UE transmits a PUCCH and/or PUSCH to the BS on the PCell and/orSCell based on power controlled in S310 (S315).

Hereinafter, various embodiments of transmission of the group TPCcommand described in S305 will be described in detail with reference tothe drawings.

FIG. 5 illustrates a method of transmitting a group TPC command andperforming monitoring according to one or more exemplary embodiment.

Referring to FIG. 5, a first TPC command for a PUCCH(PCell) and a secondTPC command for a PUCCH(SCell) are included in a single group TPCcommand and mapped to a piece of DCI. That is, in the presentembodiment, a piece of DCI is shared for power control for both thePUCCH(PCell) and the PUCCH(SCell). An example of the DCI including thesingle group TPC command may be illustrated in FIG. 4.

The DCI including the single group TPC command according to the presentembodiment is mapped to a PDCCH scrambled with TPC-PUCCH#0 (RNTI) andtransmitted. The PDCCH (PDCCH with TPC-PUCCH RNTI) related to the singlegroup TPC command is mapped to a Ccommon search space (CSS) on a PCell.In BS and UE operations, the BS generates a piece of DCI for powercontrol for both the PUCCH(PCell) and the PUCCH(SCell), scrambles aPDCCH including the DCI with a TPC-PUCCH RNTI (accurately scrambled witha CRC bit), maps the scrambled PDCCH to the CSS of the PCell, andtransmits the PDCCH to the UE. The UE monitors the CSS of the PCell inorder to receive the TPC command on the PUCCH(SCell). In this respect,the present embodiment is different from monitoring two CSSs (CSSs onPCell and PSCell) by two dual connectivity-configured UEs.

Other examples of a PDCCH mapped to the CSS includes a PDCCH scrambledwith a Random Access-Radio Network Temporary Identifier (RA-RNTI), aPDCCH scrambled with a common-RNTI (C-RNTI), a PDCCH scrambled with atemporary C-RNTI (TC-RNTI), a PDCCH scrambled with a TPC-PUSCH-RNTI, aPDCCH scrambled with an eIMTA-RNTI, a PDCCH scrambled with an SPS-RNTI,a PDCCH scrambled with a P-RNTI, a PDCCH scrambled with an SI-RNTI, orthe like.

FIG. 6 illustrates a method of transmitting a group TPC command andperforming monitoring according to one or more exemplary embodiment.

Referring to FIG. 6, a first group TPC command for a PUCCH(PCell) and asecond group TPC command for a PUCCH(SCell) are included in differentpieces of DCI. Both first DCI including the first group TPC command andsecond DCI including the second group TPC command are transmitted on thePCell. The first DCI is transmitted, being mapped to PDCCH1 scrambledwith a TPC-PUCCH#0 RNTI, and the second DCI is transmitted, being mappedto PDCCH2 scrambled with a TPC-PUCCH#0 RNTI. That is, one TPC-PUCCH RNTIvalue is commonly applied to two PDCCHs having different TPC commands(or different pieces of DCI). Further, both PDCCH1 and PDCCH2 are mappedto a CSS on a PCell. Since PDCCH1 and PDCCH2 are mapped to the same CSSand the same TPC-PUCCH RNTI value is applied to PDCCH1 and PDCCH2,information for distinguishing PDCCH1 and PDCCH2 is necessary.

For example, a carrier indicator field (CIF) may be used to distinguishPDCCH1 and PDCCH2. Specifically, the second DCI related to thePUCCH(SCell) may include the CIF. In other words, the CIF may be used todistinguish the first DCI and the second DCI. That is, the CIF may beused to distinguish the first group TPC command and the second group TPCcommand. In this case, the BS may configure cross carrier scheduling ina CCS for PUCCH(SCell)-configured UEs through RRC signaling, similarlyto cross carrier scheduling configurable in a UE-specific search space.Here, a CIF value activated in the DCI serves as an indicator whichindicates only the DCI for the PUCCH(SCell), not a serving celltransmitting a PDSCH or PUSCH as in a UE-specific search space. Thus,only one bit may be used as a CIF value. In the presence of two or morePUCCH(SCell)-configured SCells, a bit value may be increased for the CIFvalue accordingly. For example, when a one-bit CIF value is 0, a UErecognizes that corresponding DCI provides a group TPC command for aPUCCH(SCell). However, when a one-bit CIF value is 1, the CIF isreserved. Thus, cross carrier scheduling in the CCS is configuredthrough RRC signaling and is indicated (or activated) with a three-bitCIF or one-bit CIF in the DCI based on an RRC signaling configuration.Unused fields in the CIF are reserved. The UE needs to monitor a CSS ofthe PCell in order to receive the group TPC command for thePUCCH(SCell). An RRC signaling information element for cross carrierscheduling is illustrated below. Here, in order to indicate crosscarrier scheduling on the PCell, schedulingCellld needs to have a valueof a serving cell index of the PCell (that is, 0). Further, cif-presenceis activated and only three bits or one bit is activated in DCI (format3/3A).

TABLE 6 -- ASN1START CrossCarrierSchedulingConfig ::= SEQUENCE {  schedulingCellInfo CHOICE {     own SEQUENCE { -- No cross carrierscheduling       cif-Presence BOOLEAN     },     other SEQUENCE { --Cross carrier scheduling       schedulingCellId ServCellIndex,      pdsch-Start INTEGER (1..4)     }   } } -- ASN1STOP

In BS and UE operations, the BS generates first DCI for PUCCH(PCell)power control and second DCI for the PUCCH(SCell) power control. Here,the BS includes a CIF indicating the PCell in the second DCI. The BSscrambles PDCCH1 including the first DCI with a TPC-PUCCH RNTI andPDCCH2 including the second DCI with a TPC-PUCCH RNTI. The BS maps thescrambled PDCCH1 and PDCCH2 to the CSS of the PCell and transmits to theUE. The UE monitors the CSS of the PCell in order to receive a TPCcommand on the PUCCH(SCell).

According to the present embodiment, cross carrier scheduling is enablednot only for PDCCHs mapped to a UE-specific search space (USS) but alsofor PDCCHs mapped to a CSS. Further, as a CIF is used, it is notnecessary to introduce a separate RNTI for distinguishing PDCCH1 andPDCCH2.

FIG. 7 illustrates a method of transmitting a group TPC command andperforming monitoring according to one or more exemplary embodiment.FIG. 7 is different from FIG. 6 in that a new RNTI is used with respectto PDCCH2 transmitted on a CSS of a PCell.

Referring to FIG. 7, a first group TPC command for a PUCCH(PCell) and asecond group TPC command for a PUCCH(SCell) are included in differentpieces of DCI. Both first DCI including the first group TPC command andsecond DCI including the second group TPC command are transmitted on thePCell. The first DCI is transmitted, being mapped to PDCCH1 scrambledwith a TPC-PUCCH#0 RNTI, and the second DCI is transmitted, being mappedto PDCCH2 scrambled with a TPC-PUCCH-SCell RNTI. That is, different RNTIvalues are applied to two PDCCHs having different TPC commands (ordifferent pieces of DCI). The new TPC_PUCCH-SCell RNTI defined forPUCCH(SCell) power control in the present embodiment may be replacedwith a different term performing the same function.

Meanwhile, both PDCCH1 and PDCCH2 are mapped to the CSS on the PCell.PDCCH1 and PDCCH2 are mapped to the same CSS but scrambled withdifferent RNTI values, and thus information for distinguishing PDCCH1and PDCCH2 is not necessary. That is, since different RNTI values anddifferent TPC indexes are applied to the respective PDCCHs, which arethen transmitted, it is not needed to set a CIF value.

In BS and UE operations, the BS generates first DCI for PUCCH(PCell)power control and second DCI for the PUCCH(SCell) power control. The BSscrambles PDCCH1 including the first DCI with a TPC-PUCCH RNTI andPDCCH2 including the second DCI with a TPC-PUCCH-SCell RNTI. The BS mapsthe scrambled PDCCH1 and PDCCH2 to the CSS of the PCell and transmits tothe UE. The UE monitors the CSS of the PCell using the TPC-PUCCH-SCellRNTI in order to receive a TPC command on the PUCCH(SCell).

FIG. 8 illustrates a method of transmitting a group TPC command andperforming monitoring according to one or more exemplary embodiment.

Referring to FIG. 8, a first group TPC command for a PUCCH(PCell) and asecond group TPC command for a PUCCH(SCell) are included in differentpieces of DCI. First DCI including the first group TPC command istransmitted on a PCell, and second DCI including the second group TPCcommand is transmitted on a SCell.

The first DCI is mapped to PDCCH1 scrambled with a TPC-PUCCH RNTI, andPDCCH1 is mapped to a CSS of the PCell. The second DCI is mapped toPDCCH2 scrambled with a TPC-PUCCH RNTI, and PDCCH2 is mapped to a CSS ofthe SCell.

To receive PDCCH2, the UE needs to recognize in advance that PDCCH2 ismapped to the CSS of the SCell. The BS and the UE may implicitly agreethat PDCCH2 is mapped to the CSS of the SCell, or the BS may explicitlynotify the UE that PDCCH2 is mapped to the CSS of the SCell.

For example, the UE may transmit, to the BS, capability informationindicating that Multimedia Broadcast Multicast Service (MBMS) issupportable, and the BS receiving the capability information may mapPDCCH2 to the CSS of the SCell. That is, the capability information maybe implicit information transmitted to the BS so that PDCCH2 istransmitted, being mapped to the CSS of the SCell. The UE transmittingthe capability information implicitly recognizes that the UE needs tomonitor the CSS of the SCell to receive the group TPC command for thePUCCH(SCell).

The foregoing operation is possible for the following reason. A PhysicalMBMS Channel (PMCH) that is an MBMS-related physical channel istransmitted on a carrier (or SCell) other than the PCell, and aPDCCH(PDCCH with M-RNTI) needed to decode the PMCH is mapped to the CSSof the carrier (or SCell) transmitting the PMCH, not to the PCell. Thus,in order that the MBMS-supportable UE receives the MBMS, the UE needs tomonitor the CSS on the SCell transmitting the PMCH, not on the PCell.Since the UE needs to monitor the CSS of the SCell in order to receivethe MBMS, it is possible to simultaneously monitor PDCCH2 related to thegroup TPC command for the PUCCH(SCell) in the CSS on the SCell. Here,the SCell includes an uplink component carrier (UL CC) transmitting thePUCCH(SCell) and a downlink component carrier (DL CC) connected to theUL CC via SIB-2. Thus, the UE monitors the PDCCH scrambled with theTPC-PUCCH RNTI in the CSS on the DL CC.

In the present embodiment, in order that the UE monitors the CSS on theSCell to receive PDCCH2, it is required that i) the UE transmits, to theBS, capability information indicating that MBMS is supportable, and ii)the PUCCH(SCell) is configured for the UE. That is, when the UE cansupport MBMS and support the PUCCH(SCell), the UE may monitor the CSS onthe SCellin order to receive the group TPC command (or DCI). In otherwords, the UE having UE capability corresponding to mbms-SCell supportsthe PUCCH(SCell), which is configured by the BS, the UE monitors the CSSon the DL CC(SCell) connected to the UL CC(SCell) transmitting thePUCCH(SCell) via an SIB-2 link in order to receive the group TPC commandfor PUCCH(SCell) power control.

The capability information (mbms-SCell-r11) indicating that MBMS issupportable may be defined as in Table 7. The capability information maybe included in MBMS parameter information (MBMS-Parameters-r11).

TABLE 7 MBMS-Parameters-r11 ::= SEQUENCE {   mbms-SCell-r11 ENUMERATED{supported} OPTIONAL,   mbms-NonServingCell-r11 ENUMERATED {supported}OPTIONAL }

Referring to Table 7, the MBMS parameter information(MBMS-Parameters-r11) may be information included in UE-EUTRA-CapabilityIE. mbms-SCell-r11 is capability information indicating that MBMS issupportable in a SCell and may optionally be included in the MBMSparameter information. mbms-SCell-r11 displaying {supported} representsthat a corresponding UE can support reception of MBMS in the SCell.

When the capability information indicating that MBMS is supportabledisplays “supported,” the UE is expected to monitor the CSS on the SCellin order to the group TPC command for the PUCCH(SCell) later, becausethe UE can monitor the CSS on the SCell or a non-serving cell.

Alternatively, regardless of whether the UE can support MBMS, when theUE supports the PUCCH(SCell) (or when the PUCCH(SCell) is configured),the UE may monitor the CSS on the SCell in order to implicitly receivePDCCH2. In this case, the BS may also implicitly map PDCCH2 on the CSSon the SCell and transmit to the UE.

FIG. 9 illustrates an example of a corresponding relationship between aTPC index and a group TPC command according to one or more exemplaryembodiment.

Referring to FIG. 9, the BS may set a TPC index set by upper-layersignaling commonly for each UE. That is, unlike in FIG. 4, the TPC indexmay be shared between UEs, instead of setting different TPC indexes forthe UEs. This method is effective only for new PUCCH(SCell)-configuredUEs and may be applicable to a case where a TPC index is indicated usinga DCI format, as in a UE (FIG. 5), or a case where a TPC index isindicated through other DCI by exclusively using PUCCH(SCell) (FIG. 6, 7or 8), which is described in detail as follows.

Legacy UES, UEs 2/4/5, are configured as in conventionally, and the sameTPC index is set for new UEs, UEs 1/7/8 and UEs 6/10/11/12. The BS mayprovide a power value in a time-divided manner to the UEs (e.g. UE1/7/8or UE6/10/11/12). To divide time, the following equation is used.

└n_(s)/2 mod K=i(0≤i<K)   [Equation9

Referring to Equation 2, K is the number of UEs sharing one TPC index.In this example, K=3 or K=4. For example, in K=3, that is, UEs 1/7/8,the BS set in advance i=0 for UE1, i=1 for UE7, and i=2 for UE8, therebyproviding different TPC indexes to the three UEs by subframe. The UEsmay share a bit value in the same TPC field through a subframecorresponding to the value of each i. Accordingly, a TPC index mayefficiently be utilized to provide a group TPC command value.

FIG. 10 is a block diagram illustrating a UE and a BS according to oneor more exemplary embodiment.

Referring to FIG. 10, the UE 1000 includes a processor 1010, a radiofrequency (RF) module 1020, and a memory 1025. The memory 1025 isconnected to the processor 1010 and stores various pieces of informationto drive the processor 1010. The RF module 1020 is connected to theprocessor 1010 and transmits and/or receives a radio signal.

The RF module 1020 receives an upper-layer message to assign a TPC indexfrom the BS 1050. Definition and functions of the TPC index aredescribed in S300. The upper-layer message may be an RRC message. Forexample, the RRC message is TPC-PDCCH-Config in Table 2, which is usedto specify indexes and RNTIs for PUCCH and PUSCH power control. PUCCHand PUSCH power control may be set up or canceled usingTPC-PDCCH-Config. A first TPC index and a second TPC index may be set bya processor 1060 of the BS 1050 independently and individually, or inconnection with each other or identically.

The processor 1010 implements functions, processes and/or methods of theUE suggested in FIGS. 2 to 8 in the present specification. Specifically,when the RF module 1020 receives the upper-layer message, the processor1010 establishes TPC settings for the PCell and the SCell. The processor1010 uses a TPC-Index field as a TPC index to a TPC command for aPUCCH(PCell) and a TPC-Index r13 field as a TPC index to a TPC commandfor a PUCCH(SCell). That is, the processor 1010 may distinguish the TPCindex for the PCell and the TPC index for the SCell. The processor 1010may perform power control for the PUCCH(PCell) and the PUCCH(SCell)transmissions using the two TPC indexes.

Further, the RF module 1020 receives a group TPC command from the BS1050. The group TPC command is transmitted, being included in DCI.Definition and functions of the group TPC command are described in S305.In order that the processor 1010 performs both power control for thePUCCH(PCell) and power control for the PUCCH(SCell), various embodimentsof group TPC commands may be used in S305. As a method of transmitting agroup TPC command, the embodiments illustrated in FIGS. 5 to 8 may beused.

In one embodiment, the processor 1010 monitors a CSS of the PCell inorder to receive a TPC command on the PUCCH(SCell).

In another embodiment, the processor 1010 monitors the CSS of the PCellusing a TPC-PUCCH-SCell RNTI in order to receive a TPC command on thePUCCH(SCell).

In still another embodiment, the processor 1010 generates capabilityinformation indicating that MBMS is supportable and sends the capabilityinformation to the RF module 1020, and the RF module 1020 may transmit amessage in Table 3 to the BS 1050. The processor 1010 monitors a CSS ofthe SCell in order to receive the MBMS, simultaneously with monitoringPDCCH2 related to the group TPC command for the PUCCH(SCell) in the CSSon the SCell.

In yet another embodiment, regardless of whether the UE 1000 can supportMBMS, when the UE 1000 supports the PUCCH(SCell) (or when thePUCCH(SCell) is configured), the processor 1010 may monitor the CSS onthe SCell in order to implicitly receive PDCCH2.

When the group TPC command is received by monitoring, the processor 1010performs PUCCH and PUSCH power control in the PCell and the SCell basedon the group TPC command. Specifically, the processor 1010 may performpower control for the PUCCH of the SCell based on an accumulative powercontrol mode. For example, when a group TPC command for aPUCCH-configured SCell is received, the processor 1010 accumulates aPUCCH power control value according to the group TPC command and aprevious value.

The RF module 1065 transmits the PUCCH(PCell) and/or PUCCH(SCell) fromthe UE 1000 to the BS 1050 according to power controlled by the groupTPC command.

The BS 1050 includes a memory 1055, a processor 1060, and a RF module1065. The memory 1055 is connected to the processor 1060 and storesvarious pieces of information to drive the processor 1060. The RF module1065 is connected to the processor 1060 and transmits and/or receives aradio signal. Specifically, the RF module 1065 transmits an upper-layermessage to assign a TPC index to the UE 1000. The RF module 1065transmits a group TPC command to the UE 1000 on a PCell and/or SCell.Further, the RF module 1065 receives capability information related toMBMS in Table 3 from the UE 1000. The RF module 1065 receives aPUCCH(PCell) and/or PUCCH(SCell) from the UE 1000.

The processor 1060 implements functions, processes and/or methodsrelated to the BS illustrated in FIGS. 2 to 8 in the presentspecification.

In one embodiment, the processor 1060 generates a piece of DCI for powercontrol for both of a PUCCH(PCell) and a PUCCH(SCell), scrambles a PDCCHincluding the generated DCI with a TPC-PUCCH RNTI, and maps thescrambled PDCCH to a CSS of the PCell.

In another embodiment, the processor 1060 generates first DCI forPUCCH(PCell) power control and second DCI for PUCCH(SCell) powercontrol. Here, the processor 1060 includes a CIF indicating the PCell inthe second DCI. The processor 1060 scrambles PDCCH1 including the firstDCI with a TPC-PUCCH RNTI and PDCCH2 including the second DCI with aTPC-PUCCH RNTI. The processor 1060 maps the scrambled PDCCH1 and PDCCH2to the CSS of the PCell.

In still another embodiment, the processor 1060 generates first DCI forPUCCH(PCell) power control and second DCI for PUCCH(SCell) powercontrol. The processor 1060 scrambles PDCCH1 including the first DCIwith a TPC-PUCCH RNTI and PDCCH2 including the second DCI with aTPC-PUCCH-SCell RNTI. The processor 1060 maps the scrambled PDCCH1 andPDCCH2 to the CSS of the PCell.

In yet another embodiment, the processor 1060 maps PDCCH1 scrambled withthe TPC-PUCCH RNTI to the CSS of the PCell and maps PDCCH2 scrambledwith the TPC-PUCCH RNTI to a CSS of the SCell. This is a case where theRF module 1060 receives, from the UE 1000, capability informationindicating that MBMS is supportable.

According to one or more exemplar embodiment, a base station, e.g., anevolved NodeB, controls transmit power of uplink channels in a wirelesscommunication system. The base station may include a system including aprocessor, an RF module, and a memory. For example, the system of thebase station may include the processor 1060, the RF module 1065, and thememory 1055 shown in FIG. 10.

In an example, one or more processors of the base station may configure,for a UE, a primary serving cell on which a first uplink control channelis transmitted from the UE. The first uplink control channel may includeuplink control information of the primary serving cell. The one or moreprocessors of the base station may configure, for the UE, a secondaryserving cell on which a second uplink control channel is transmittedfrom the UE. The second uplink control channel may include uplinkcontrol information of the secondary serving cell. Further, the one ormore processors of the base station may configure a first TPC commandand a second TPC command in a single TPC command group, the first TPCcommand being associated with transmit power of the uplink controlinformation of the primary serving cell, the second TPC command beingassociated with transmit power of the uplink control information of thesecondary serving cell.

The one or more processors of the base station may scramble downlinkcontrol information based on an identifier associated with a TPC. Thedownlink control information includes the single TPC command group.

One or more RF modules may transmit, to the UE, a downlink controlchannel including the scrambled downlink control information. Further,the one or more RF modules ma establish a connection with the UE throughthe primary serving cell, and receive a Radio Resource Control (RRC)message through the primary serving cell.

The one or more processors of the base station may assign an index forthe first TPC command and an index for the second TPC command. The indexfor the first TPC command associated with the primary serving cellconfigured for the UE is different from the index for the second TPCcommand associated with the secondary serving cell configured for theUE.

The one or more RF modules may transmit, through a Radio ResourceControl (RRC) message, a TPC- Physical Downlink ControlChannel(PDCCH)-Config message to assign, for the UE, the index for thefirst TPC command and the index for the second TPC command. For example,the downlink control channel is a PDCCH associated with theTPC-PDCCH-Config message.

As described above, the index for the first TPC command may havedifferent bit sizes, according to downlink control information format 3or downlink control information format 3A. Further, the index for thesecond TPC command may have different bit sizes, according to downlinkcontrol information format 3 or downlink control information format 3A.The single TPC command group may include a third TPC command forcontrolling transmit power of an uplink channel of another UE. In anexample, a first piece of downlink control information including thesingle TPC command group is scrambled using a first TPC Physical UplinkControl Channel (PUCCH) Radio Network Temporary Identifier (RNTI), and asecond piece of downlink control information different from the firstpiece of downlink control information is scrambled using a second TPCPUCCH RNTI. The first TPC PUCCH RNTI and second TPC PUCCH RNTI havedifferent values.

The first TPC command is associated with transmit power of the firstuplink control channel, and the first uplink control channel may furtherinclude uplink control information of at least one secondary servingcell grouped, together with the primary serving cell, in a first servingcell group. The second TPC command is associated with transmit power ofthe second uplink control channel, and the second uplink control channelmay further include uplink control information of at least one secondaryserving cell grouped, together with the secondary serving cell, in asecond serving cell group.

The one or more processors may map the downlink control channel to acommon search space of the primary serving cell for the transmission ofthe downlink control channel.

According to one or more exemplary embodiment, a system of a basestation to transmit a TPC command in a wireless communication systemsupporting CA is provided.

One or more RF modules of the base station may establish a connectionwith a UE through a primary serving cell (PCell), and transmit, to theUE, a Radio Resource Control (RRC) message. The RRC message may includea first Transmit Power Control (TPC) index associated with a PhysicalUplink Control Channel (PUCCH) transmission on the PCell and a secondTPC index associated with a PUCCH transmission on a secondary servingcell (SCell), the SCell together with the PCell being configured asserving cells for the UE.

The one or more RF modules may transmit a Physical Downlink ControlChannel (PDCCH) by mapping the PDCCH to a common search space of thePCell. A Downlink Control Information (DCI) format of the PDCCH mayinclude a first TPC command for controlling transmit power of the PUCCHtransmission on the PCell and a second TPC command for controllingtransmit power of the PUCCH transmission on the SCell.

One or more processors of the base station may determine a value of thefirst TPC command to control transmit power of the PUCCH transmission onthe PCell and determine a value of the second TPC command to controltransmit power of the PUCCH transmission on the SCell, the value of thefirst TPC command being mapped in the DCI format based on the first TPCindex and the value of the second TPC command being mapped in the DCIformat based on the second TPC index.

According to one or more exemplary embodiment, a system for a UE toreceive a TPC command in a wireless communication system supporting CAis provided. The system for the UE may include a processor, an RFmodule, and a memory. For example, the system may be a system-on-chipand may include the processor 1010, the RF module 1020, and the memory1025 shown in FIG. 10.

An RF module of the system may be configured to establish a connectionwith a base station through a primary serving cell (PCell), and toreceive a Radio Resource Control (RRC) message. The RRC message mayinclude a first Transmit Power Control (TPC) index associated with aPhysical Uplink Control Channel (PUCCH) transmission on the PCell and asecond TPC index associated with a PUCCH transmission on a secondaryserving cell (SCell), the SCell together with the PCell being configuredas serving cells for the UE.

A processor of the system may be configured to detect a PhysicalDownlink Control Channel (PDCCH) by monitoring a common search space ofthe PCell. A Downlink Control Information (DCI) format of the PDCCH mayinclude a first TPC command for controlling transmit power of the PUCCHtransmission on the PCell and a second TPC command for controllingtransmit power of the PUCCH transmission on the SCell. The processor maybe configured to identify the first TPC command and the second TPCcommand from the DCI format based on the first TPC index and the secondTPC index, respectively, to control transmit power of the PUCCHtransmission on the PCell based on a value of the first TPC command, andto control transmit power of the PUCCH transmission on the SCell basedon a value of the second TPC command.

The RF module may configure a CA for the UE using the PCell and aplurality of SCells. The processor may determine the PUCCH transmissionon the SCell selected from among the plurality of SCells. The RRCmessage is received through the PCell.

The DCI format may correspond to DCI format 3, and each of the first TPCindex and the second TPC index corresponds to different 2-bit data ofthe DCI format 3.

the DCI format may correspond to DCI format 3A, and each of the firstTPC index and the second TPC index corresponds to different 1-bit dataof the DCI format 3A. The DCI format may include a third TPC command forcontrolling transmit power of the PUCCH transmission of another UE.

The processor may identify the first TPC command, the second TPCcommand, and the third TPC command from the PDCCH scrambled with one TPCPUCCH Radio Network Temporary Identifier (RNTI). The RRC message mayfurther include information of the TPC PUCCH RNTI. The processor maydetermine first uplink control information (UCI) to be included in thePUCCH transmission on the PCell, and second UCI to be included in thePUCCH transmission on the SCell.

The processors may include an application-specific integrated circuit(ASIC), another chipset, a logic circuit, and/or a data processingdevice. The memories may include a Read-Only Memory (ROM), a RandomAccess Memory (RAM), a flash memory, a memory card, a storage mediumand/or another storage device. The RF modules may include a basebandcircuit for processing a wireless signal. When an embodiment is embodiedas software, the described scheme may be embodied as a module (process,function, or the like) that executes the described function. The modulemay be stored in a memory, and may be executed by a processor. Thememory may be disposed inside or outside the processor, and may beconnected to the processor through various well-known means.

In the described exemplary system, although methods are described basedon a flowchart as a series of steps or blocks, aspects of the presentinvention are not limited to the sequence of the steps and a step may beexecuted in a different order or may be executed in parallel withanother step. In addition, it is apparent to those skilled in the artthat the steps in the flowchart are not exclusive, and another step maybe included or one or more steps of the flowchart may be omitted withoutaffecting the scope of the present invention.

What is claimed is:
 1. A method comprising: configuring, for a userequipment (UE), a first uplink carrier on which a first physical uplinkshared channel (PUSCH) is transmitted from the UE; configuring, for theUE, a second uplink carrier on which a second PUSCH is transmitted fromthe UE; configuring, for the UE, a first Transmit Power Control (TPC)command and a second TPC command in a single TPC command group, thefirst TPC command being associated with transmit power of the firstPUSCH, the second TPC command being associated with transmit power ofthe second PUSCH; assigning a first index for the first TPC command anda second index for the second TPC command. scrambling downlink controlinformation (DCI) based on an identifier associated with a TPC, the DCIcomprising the single TPC command group; transmitting the scrambled DCIto the UE.
 2. The method of claim 1, further comprising: mapping the DCIto Physical Downlink Control Channel (PDCCH), wherein the DCI isscrambled with a TPC-PUSCH radio network temporary identifier (RNTI). 3.The method of claim 1, wherein the first index is different from thesecond index.
 4. The method of claim 1, further comprising:transmitting, through a Radio Resource Control (RRC) message, the indexfor the first TPC command and the index for the second TPC command. 5.The method of claim 1, wherein the single TPC command group comprises athird TPC command for controlling transmit power of an uplink channel ofanother UE.
 6. A method comprising: receiving, configurationinformation, wherein the configuration information comprises:configuration of a first uplink carrier on which a first physical uplinkshared channel (PUSCH) is transmitted, configuration of a second uplinkcarrier on which a second PUSCH is transmitted, configuration of a firstTransmit Power Control (TPC) command associated with the first PUSCH anda first index for the first TPC command, configuration of a second TPCcommand associated with the second PUSCH and a second index for thesecond TPC command, wherein the first TPC command and the second TPCcommand is in a single TPC command group; receiving a Physical DownlinkControl Channel (PDCCH), wherein a Downlink Control Information (DCI)format of the PDCCH comprises the single TPC command group; identifyingthe first TPC command and the second TPC command from the DCI formatbased on the first index and the second index, respectively; determiningfirst transmit power of the PUSCH transmission according to the firstTPC command and second transmission power of the second PUSCHtransmission according to the second TPC command; transmitting the firstPUSCH using first transmit power and the second PUSCH using the secondtransmission power.
 7. The method of claim 6, wherein the DCI isscrambled with a TPC-PUSCH radio network temporary identifier (RNTI). 8.The method of claim 6, wherein the first index is different from thesecond index.
 9. The method of claim 6, wherein the configurationinformation is received through a Radio Resource Control (RRC) message.10. The method of claim 6, wherein the single TPC command groupcomprises a third TPC command for controlling transmit power of anuplink channel of another UE.
 11. The method of claim 6, wherein theconfiguration information further comprises information of the TPC PUSCHRNTI.
 12. A base station, comprising: at least one processor configuredto configure, for a user equipment (UE), a first uplink carrier on whicha first physical uplink shared channel (PUSCH) is transmitted from theUE; configure, for the UE, a second uplink carrier on which a secondPUSCH is transmitted from the UE; configure a first Transmit PowerControl (TPC) command and a second TPC command in a single TPC commandgroup, the first TPC command being associated with transmit power of thefirst PUSCH, the second TPC command being associated with transmit powerof the second PUSCH; assign a first index for the first TPC command anda second index for the second TPC command; and scramble downlink controlinformation (DCI) based on an identifier associated with a TPC, the DCIcomprising the single TPC command group; and a transceiver, configuredto transmit the scrambled DCI to the UE.
 13. The base station of claim12, wherein the at least one processor is further configured to map theDCI to Physical Downlink Control Channel (PDCCH), wherein the DCI isscrambled with a TPC-PUSCH radio network temporary identifier (RNTI).14. The base station of claim 12, wherein the first index is differentfrom the second index.
 15. The base station of claim 12, wherein: thetransceiver, is further configured to transmit, through a Radio ResourceControl (RRC) message, the index for the first TPC command and the indexfor the second TPC command.
 16. The base station of claim 12, whereinthe single TPC command group comprises a third TPC command forcontrolling transmit power of an uplink channel of another UE.